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At least 1,549 records · Page 86Linked to original sources
PubMed2003

[Effects of plastic film mulching on soil temperature and moisture and on yield formation of spring wheat].

Field experiments were carried out to study the effects of plastic film mulching on soil temperature and moisture, and on yield formation of spring wheat. The results showed that plastic film mulching could increase soil temperature with "U" variances in the whole growth period of spring wheat. Plastic film mulching could also increase soil available water by restraining evaporation and elevating deep water to the layer useable for roots. The promotion of soil temperature and soil water content under plastic film mulching was favorable to the development and water use of spring wheat in its earlier stage. Root developments were restrained when mulching in later stage of spring wheat, with decreases in crop water consumption and water use efficiency, and there was no significant effects on yield formation. The spring wheat yields under control (CK), pre-sowing irrigation (W), mulching for whole stage (M), pre-sowing irrigation adding mulching for 30 days (WM30), pre-sowing irrigation adding mulching for 60 days (WM60), and pre-sowing irrigation adding mulching for whole stage (WMw) were 2 554, 2,424, 2,750, 3,138, 3,305, and 3,123 kg.hm-2, respectively, and the optimum mulching time was at 40-60 days.

Biomass↗
PubMed1992

[The behavior of fiber-reinforced plastics during laser cutting].

The pattern of the organic emissions, which are produced by processing of fibre reinforced plastics (epoxy resins reinforced by aramid and glass fibres and phenol resins reinforced by aramid fibre) with laser beam was studied and the concentrations of the main components determined. Despite the application of plastic materials with different chemical structures, the observed patterns are very similar. Mainly aromatic hydrocarbons are emitted, especially benzene and toluene, as well as some heteroatom-containing aromatic hydrocarbons (e.g. phenol). By use of oxygen as process gas the emissions during cutting of glass fibre reinforced plastics can be reduced, while they will be constantly high with aramid fibre reinforced plastics.

Air Pollution↗
PubMed2004

Evaluating the effects of plasticizer interactions with HPMC on the tack-behavior of polymer film-forming coating solutions.

Tack is a concept that is widely used to describe the forces or energies involved in the separation of two parallel surfaces initially in contact through an intervening thin liquid film. The tackiness may cause tablets to stick with each other or to the walls of the coating apparatus. In this study, the HPMC coating solutions were evaluated for their tackiness and the effects of interactions between the polymer and plasticizers on the tack behavior of HPMC film-forming coating solutions were investigated, using type TA-XT2 texture analyzer. It was found that experimental factors such as the contact time, rate of separation and volume of the film-forming test solution could effectively influence the magnitude of tack behavior. Moreover, up to certain levels, the addition of plasticizers such as PEG 400 & 1000 and of triacetin caused a reduction in the tack value of the polymer solutions. It was concluded that in general, the tackiness depended upon the molecular weight and/or type and concentration of a plasticizer. The efficiency of plasticizers used to reduce the tackiness of HPMC solutions ranked as PEG1000 > triacetin > PEG400.

Journal Article↗
PubMed2006

[Isolation and purification of BMScs of GFP transgenic mouse using the method of adhering to cuture plastic in different time].

OBJECTIVE: To adopt the method of adhering to culture plastic in different time for cultivating and purifying BMSCs of green fluorescent protein (GFP) transgenic mice. METHODS: Bone marrow cells isolated from GFP transgenic mice are directly planted in culture flask and an exchange of the total volume medium is made at different time. Then the cells adhering to culture plastic are differently counted according to the cell types and are examined by immunohistochemistry using the antibodies of CD44, CD45 and CD54 in three days. Moreover, the cells after the exchange of the total volume medium in 4 hours, 8 hours and 24 hours are selected and successively subcultured down to the fifth passage. Then the result of amplification is calculated and the cells are examined by immunohistochemistry using the antibodies of CD44, CD45 and CD54. RESULTS: With the extending of the time for the first exchange of medium, the density of cells adhering to culture plastic increased accordingly, but the BMSCs proportion decreased. The cells after first exchange of medium in 4 hours had high BMSCs proportion but low BMSCs density, and the cells in 24 hours had high BMSCs density and low BMSCs proportion. However, the cells in 8-10 hours had high BMSCs density and also high BMSCs proportion. The subcultured BMSCs could stably express GFP. CONCLUSION: The method of adhering to culture plastic in different time for cultivating and purifying BMSCs of GFP transgenic mice is effective. It is suitable to make the first exchange of total volume medium in 8-10 hours. The subcultured cell has the capacity for amplification and will probably be a seed cell for the research of tissue engineering and gene therapy.

Animals↗
PubMed2006

The phenotypic variance within plastic traits under migration-mutation-selection balance.

How phenotypic variances of quantitative traits are influenced by the heterogeneity in environment is an important problem in evolutionary biology. In this study, both genetic and environmental variances in a plastic trait under migration-mutation-stabilizing selection are investigated. For this, a linear reaction norm is used to approximate the mapping from genotype to phenotype, and a population of clonal inheritance is assumed to live in a habitat consisting of many patches in which environmental conditions vary among patches and generations. The life cycle is assumed to be selection-reproduction-mutation-migration. Analysis shows that phenotypic plasticity is adaptive if correlations between the optimal phenotype and environment have become established in both space and/or time, and it is thus possible to maintain environmental variance (V(E)) in the plastic trait. Under the special situation of no mutation but maximum migration such that separate patches form an effective single-site habitat, the genotype that maximizes the geometric mean fitness will come to fixation and thus genetic variance (V(G)) cannot be maintained. With mutation and/or restricted migration, V(G) can be maintained and it increases with mutation rate but decreases with migration rate; whereas VE is little affected by them. Temporal variation in environmental quality increases V(G) while its spatial variance decreases V(G). Variation in environmental conditions may decrease the environmental variance in the plastic trait.

Animal Migration↗
PubMed2006

[Clinical features and surgery in children with plastic bronchitis].

OBJECTIVE: To review the clinical features and therapeutic experience in children with plastic bronchitis. METHODS: Fourteen children with plastic bronchitis were reviewed retrospectively, 12 of which were under two years old. The clinical features are characterized by sudden onset, episodes of profound hypoxia and respiratory tract obstruction. SaO2 was between 0.70 and 0.80 even with mask oxygen inhalation. Eight cases were pyretic, 4 cases expectorated jel-like bronchial casts. The chest X-ray picture showed patchy consolidation or atelectasis unilaterally (10 cases) or bilaterally (2 cases). Pulmonary marking thickening and patchy shadow were observed in 2 cases. Twelve cases underwent rigid bronchoscopy and the bronchial casts were removed. Two cases underwent endotracheal intubation. RESULTS: Eight cases of 12 children received therapeutic bronchoscopy were cured. Other 4 cases had second therapeutic bronchoscopy and bronchial casts were removed again in 3 cases, one died from pulmonary hemorrhage. Two cases who underwent endotracheal intubation died from the multiple organ failure (MOF). Pathologic results showed:the bronchial casts were composed mainly of mucus and fibrin, inflammatory cell infiltrate were observed in 6 cases (Type 1, inflammatory), no cellular infiltrate occurred in 8 cases (Type 2, acellular). CONCLUSIONS: Plastic bronchitis is a severe and dangerous disease. The branching plastic casts may obstruct part or the entire tracheobronchial, causing respiratory failure. Bronchoscopy and pathologic examination are essential for it's diagnosis and treatment.

Airway Obstruction↗
PubMed2006

[Anatomical and water physiological plasticity of Grewia biloba var. parviflora leaf and secondary xylem].

Based on the anatomical observations of leaf and secondary xylem as well as the measurements of leaf water physiological parameters, this paper studied the anatomical and water physiological plasticity of Grewia biloba var. parviflora growing in different succession stage communities. The results showed that G. biloba var. parviflora leaf was characterized by thin bifacial with thin cuticle and few stoma, indicating that it was mesophyte anatomically, while the secondary xylem had typical xeromorphic traits, such as short and thin vessel, high vessel frequency, low percentage single pores, and short fibers and rays. G. biloba var. parviflora had high plasticity in the anatomical structure and water physiological features of leaf and secondary xylem, and the plasticity index was in the order of secondary xylem anatomical structure (0. 24) > water physiological traits (0. 19) > leaf anatomical structure (0. 18). Compared with those growing in mixed forest and Platycladus orientalis forest, the individuals of G. biloba var. parviflora in shrub communities had the xeromorphic traits in the aspects of (1) their secondary xylem had shorter vessel elements, higher vessel frequency, less single porous percentage, lower rays, higher relative conductivity and lower vulnerability index, and (2) their leaf had lower water potential, lower water content and free water content, higher bound water content, high ratio of bound to free water content, and less specific leaf area. The phenotypic plasticity, both anatomical and physiological, made G. biloba var. parviflora tolerate to the drought at earlier succession stages and better adapt to the mesophytic condition at later stages, and consequently, become a widely distributed and dominant species in mixed forests.

Adaptation, Physiological↗
PubMedDate not supplied

Exploiting the "toothpick effect" of the Cytobrush by plastic embedding of cervical samples.

The introduction of the combined spatula-Cytobrush sampling method has increased the diagnostic accuracy of cervical cytology. However, the smears from a small number of cases contained epithelial fragments dislodged by the "toothpick effect" of the Cytobrush. Due to their thickness, these epithelial fragments in the smears are very difficult (if not impossible) to scrutinize and are thus undiagnosable. The presence of only such fragments in smears led to false-negative diagnoses in two cases of invasive carcinoma. To solve this problem, these epithelial fragments were embedded in plastic, with thin sections prepared from the blocks. This paper presents the morphologic features and diagnostic accuracy of 77 such problem cases (found among 50,000 cases with spatula-Cytobrush smears) to which this method was applied. In almost all cases, the diagnosis on the plastic-embedded sections matched the diagnosis on the colposcopically directed biopsy. Of these 77 patients, the biopsy diagnosis showed 5 severe dysplasias, 6 carcinomas in situ, 1 squamous-cell carcinoma, 2 adenocarcinomas in situ and 2 adenocarcinomas. In addition, data are presented concerning the nuclear-size and shape-factor differences in smears versus plastic-embedded sections, and the stereologic consequences of smearing and cutting these epithelial fragments are discussed. These plastic-embedded sections are well suited for use in quantitative microscopy, as well as for diagnostic purposes.

Adenocarcinoma↗
PubMedDate not supplied

Plastic deformation in pediatric fractures: mechanism and treatment.

The plastic deformation often observed in children's long bone fractures is due largely to the complex nature of the molecular and histologic aspects of pediatric bone. Pediatric cortical bone has a lower mineral content than adult bone, accounting in part for its different material properties. Although plasticity allows children's long bones to absorb more energy prior to fracture, a significant deformity may persist after injury. An algorithm and technique for treatment of plastic deformation of the radius and ulna, the two most commonly involved bones in plastic deformation, are reviewed.

Adolescent↗
PubMed1986

Stability of ampicillin trihydrate suspension in amber plastic oral syringes.

The stability of ampicillin trihydrate oral suspension stored in amber plastic oral syringes was studied. Commercially available ampicillin trihydrate powder for oral suspension was reconstituted according to manufacturer's instructions and drawn into 5-mL amber polypropylene plastic oral syringes. The syringes were divided into groups and stored at -20, 4, 25, 60, or 80 degrees C. Powder from two additional lots was similarly reconstituted and packaged and stored at 80 degrees C only to assess interlot variability. Immediately after reconstitution and at specified times during storage, three syringes at each storage temperature were removed and their contents analyzed for ampicillin trihydrate concentration by a spectrophotometric assay. Samples stored at frozen (-20 degrees C) or refrigerated (4 degrees C) temperature retained at least 90% of the initial ampicillin concentration throughout the 47-day study period. Samples stored at room temperature retained at least 90% of the initial ampicillin concentration for 30 days and exhibited an apparent zero-order degradation rate. Samples stored at heated temperatures (60 and 80 degrees C) exhibited an apparent first-order degradation process, with the concentration of ampicillin decreasing to less than 90% of initial concentration within two hours. Reconstituted ampicillin trihydrate powder for oral suspension is stable for at least 30 days when stored at room, refrigerated, or frozen temperature in the amber plastic oral syringes studied. The expiration dates recommended by the manufacturer for ampicillin trihydrate suspension stored in its original container can also be used for reconstituted suspension stored in these amber plastic syringes.

Ampicillin↗
PubMed1984

Traumatic plastic deformation of the radius and ulna. A closed method of correction of deformity.

More than 50 cases of plastic deformation of the forearm in children have been reported in the literature, but no method of reduction other than osteoclasis has been described. Fourteen patients with plastic deformation of one or both bones of the forearm were observed over a period of five years. Of these 14, nine were cared for acutely, and a closed reduction was performed by placing the apex of the plastically deformed bone over a fulcrum and applying significant pressure for several minutes. The average correction was 85% of the angulation present prior to reduction. The clinical findings in these patients treated by closed reduction were compared with those observed in untreated cases seen by the authors and those in the literature. Early reduction of the plastic deformation decreased the clinical deformity, allowed treatment of adjacent fractures, and led to earlier return of full pronation and supination of the forearm.

Adolescent↗
PubMed1984

The plasticity of intellectual development: insights from preventive intervention.

Debates regarding the plasticity of intelligence are often fired by a confusion between 2 distinct realms of development, that is, between developmental functions (e.g., a group's average IQ over time) and individual differences (e.g., the relative rank ordering of individual IQs within a group). Questions concerning the stability of these 2 realms are statistically independent. Thus there are 2 kinds of intellectual plasticity, and there may be no developmental convergences between them. In the present study, data from an early intervention program were used to investigate the 2 kinds of plasticity separately and to examine certain possible convergences between them. The program involved children at risk for developmental retardation who were randomly assigned at birth to 2 rearing conditions (i.e., educational daycare vs. no educational intervention) and whose intellectual development was then studied longitudinally to 4 years of age. Our findings indicate that developmental functions are moderately alterable through systemic early education, particularly after infancy, whereas individual differences are moderately stable, again particularly after infancy. They also indicate that the 2 kinds of plasticity are independent; the alteration of developmental functions through daycare affects neither the stability nor the determinants of individual differences. We discuss the implications that these findings have for current models of mental development, for the nature-nurture debate, and for arguments concerning the efficacy of early intervention programs.

Child Day Care Centers↗
PubMedDate not supplied

The efficacy of adhesive plastic incise drapes in preventing wound contamination.

A direct method of tracing the bacterial indicators (Human Albumin Microspheres) for evaluation of adhesive plastic incision drapes was used. The particles were sprayed on the prepared skin beneath the plastic incision drape in 30 operations. At the end of the operation, wound irrigates were collected for retrieval of the particles. No particles could be detected in any of the procedures studied. It was shown that, when a plastic incise drape is properly applied, it conforms to the skin and no air bubbles or pockets of fluid will form beneath or around the incised edge of the drape. It will remain tightly adherent to the skin throughout the operative procedure. Used in this manner, plastic incise drapes can aid in preventing the migration of skin microbes into the surgical wound as was demonstrated by the complete absence of simulated bacterial indicators in all 30 of the wound irrigates that were examined.

Disinfection↗
PubMed1995

[Reconstructive-plastic surgery in bladder exstrophy].

Among 234 children with exstrophy of the urinary bladder 112 were subjected to reconstructive-plastic operation after G. A. Pair. A good result was produced in 71 cases. In 27 children a satisfactory result was attained only after repeated operations. Reconstructive-plastic interventions had no positive effect in 14 children. By means of electrophysiological and morphological methods three degrees of underdevelopment of the muscular coat of an urinary bladder affected by exstrophy were distinguished. In I degree plastics of the bladder with local tissues is indicated, in II degree the indications are relative, in III degree a plastic operation is not indicated. Choice of the operative method on basis of the morphofunctional condition of the bladder with exstrophy, the use of microsurgical techniques, the formation of a closed pelvic ring, and antireflux operations on the ureters improve the immediate and late-term results of reconstructive-restorative surgical interventions.

Age Factors↗
PubMed1986

Levels of plasticizer in the frequent plasma donor.

Di-2-ethylhexyl phthalate (DEHP), a commonly employed plasticizer reported to be carcinogenic in rats and mice, has been confirmed to leach from all plastic component parts of the equipment employed in plasma donation. Resident aqueous solutions of both sodium chloride and sodium citrate were found to contain only trace levels of DEHP (0.03 ppm), while stored plasma samples contained levels at least one order of magnitude higher (0.4 ppm). Since at least 5% of all plasma donations in the Los Angeles area are deemed to be of the high frequency classification, investigation into repeated red blood cell exposure to DEHP was considered imperative. However, there was no difference in the levels of DEHP found in the plasma of the frequent plasma donor (50-60 times per annum) relative to the first-time donor. It is concluded that there is no increased contamination threat to frequent plasma donation from migrating plasticizer via red blood cell exposure, at least during the collection process. Furthermore, there is no more risk to recipients of plasma products from frequent donors than from occasional donors. It would seem that the ambient level of DEHP to be expected in stored frozen plasma products averages no greater than about 0.5 ppm.

Blood Donors↗
PubMedDate not supplied

Outcomes research in facial plastic surgery: a review and new directions.

Outcomes research is a fast-growing field of study that focuses on patient-related aspects of medical or surgical outcomes such as satisfaction and quality of life. In the realm of facial plastic surgery, many outcomes are subjective evaluations based on the patient and physician's judgment as to the surgical result, but little has been done to quantify these qualitative results in an objective manner. This paper discusses the basis for outcomes research and suggests its application to the field of facial plastic surgery. Four new facial plastic outcomes instruments have been developed and are provided for the potential use in measuring the quality of life results of rhytidectomy, rhinoplasty, blepharoplasty, and skin rejuvenation procedures.

Humans↗
PubMed2006

[National survey of the deep vein thrombosis in plastic and aesthetic surgery, consequences and guidelines].

This first French national survey of the deep vein thrombosis and embolism risk during plastic and aesthetic surgery shows the reality of this complication. Eighty percent of the french plastic surgeons had deep vein thrombosis in their patients and 53% had pulmonary embolism. There are no guidelines in our speciality in French. The author reviews the bibliography and guidelines of all the other societies around the world as experts' recommendations during the national congress of the French Plastic Reconstructrice and Aesthetic Surgery (SOF.CPRE) in 2004.

France↗
PubMed2002

New microsurgical applications: implications for the infrastructures of plastic surgery.

As a technical innovation, microsurgery has changed concepts and strategies throughout plastic surgery. The infrastructures of plastic surgery currently are evolving in ways that make the identity and future of the specialty uncertain. Microsurgery also may be a basis for fresh thoughts in these areas of infrastructure. This article touched on some areas where microsurgery could be an important element in organizational development, namely patient population identification, economic strategies, academic organization, and medical education. More thorough exploration of these ideas and identification of others may result in a new foundation for plastic surgery with microsurgery as a key element.

Bone Transplantation↗